Optical disc device with normal resolution signal selection filter

1. An optical disc device comprising: photoelectric conversion means which converts a reflected light from an optical disc medium into an electric signal to generate a readout signal; a super resolution signal selection filter through which a super resolution signal component of the readout signal is passed; a normal resolution signal selection filter through which a normal resolution signal component of the readout signal is passed; first adaptive equalizing means which adaptively equalizes a signal passed through the super resolution signal selection filter while adaptively changing a tap coefficient; second adaptive equalizing means which adaptively equalizes a signal passed through the normal resolution signal selection filter while adaptively changing a tap coefficient; subtracting means which subtracts an output signal of the second adaptive equaling means from an output signal of the first adaptive equalizing section; and binarizing means which binaries an output signal of the subtracting section to read digital information recorded on the optical disc medium.

2. The optical device according to claim 1 , wherein the super resolution signal selection filter is a high pass filter, and the normal resolution signal selection filter is a low pass filter with a cutoff frequency higher than that of the high pass filter.

3. An optical disc device comprising: photoelectric conversion means which converts a reflected light from an optical disc medium into an electric signal to generate a first readout signal; a normal resolution signal selection filter which extracts a normal resolution signal component as a second readout signal from the first readout signal; a delay circuit which delays a phase of the first readout signal by a predetermined amount with respect to the second readout signal; subtracting means which subtracts the second readout signal from the first readout signal passed through the delay circuit; binarizing means which binaries an output signal of the subtracting section to read digital information recorded on the optical disc medium; a first phase/gain adjuster which adjusts a phase and gain of a signal passed through the delay circuit; and a second phase/gain adjuster which adjusts a phase and gain of a signal passed through the normal resolution signal selection filter; wherein the subtracting circuit subtracts an output of the second phase/gain adjuster from an output of the first phase and gain adjuster.

4. The optical disc device according to claim 3 , wherein the binarizing means is a Viterbi decoder, and the first phase/gain adjuster and the second phase/gain adjuster are adaptive equalizing means which adaptively equalize the respective first readout signal and the second readout signal while adaptively changing a tap coefficient according to an output of the Viterbi decoder.

5. The optical disc device according to claim 3 , wherein the normal resolution signal selection filter has a mark length determination device and a switch which turns on and off a signal, and the switch is turned on to pass the first readout signal through the second phase/gain adjuster when the mark length determination device determines that the first readout signal is caused by a mark longer than a predetermined mark length.

6. The optical disc device according to claim 3 , wherein the normal resolution signal selection filter is a low pass filter.